Reducing idle power consumption in a networked battery operated device

ABSTRACT

An improved method and system for reducing the power consumption of computing devices capable of communicating over a wireless network allows longer device operation and/or the use of smaller batteries. The wireless computing device supports a low power channel for receiving control signals during idle periods of operation. When the computing device is idle, the device is configured to power down all of its components with the exception of the circuitry required to power the low power channel. As such, the channel is maintained in an active state for receiving signals during both idle and non-idle periods, or in an embodiment, only during idle periods. When another device wishes to communicate with the wireless computing device, the low power channel passes a “wake-up” signal to the device indicating that the device be powered up from the idle mode of operation. A host RF component that is coupled to the network via a host computer generates this wake-up signal in an embodiment of the invention.

TECHNICAL FIELD OF THE INVENTION

The present invention relates generally to wireless computing devices,and more particularly to power management in wireless computing deviceshaving batteries for power sources.

BACKGROUND

Wireless computing devices, such as laptop computers, personal digitalassistant devices, etc., that communicate with other devices throughwireless signals are becoming increasingly popular. Wireless computingdevices are typically battery-powered. Since the amount of power abattery can provide is rather limited, minimizing the power consumptionof a device in order to extend its operation time is an importantconsideration in the design of battery operated wireless devices.

A particular component of a wireless device that consumes a significantamount of power is the network interface card (NIC), which handles thewireless transmission and reception of network communication data. Ithas been estimated that on average, about 20% of the total poweravailable to a wireless device is dissipated as a result of theconnection of a NIC, or other wireless LAN interface component. Thisphenomenon is due to the fact that the NIC and wireless device must bein a constant “listening” state in order to receive and transmit datavia the network. As a result, battery power is used to power the deviceand the NIC even when no message is being sent or transmitted.

To overcome this challenge, various schemes for reducing the batteryconsumption in wireless devices have been developed and implementedwithin conventional wireless devices. One such power management schemeinvolves completely powering off the NIC of the device during periods inwhich no data communication is occurring for that device. While thismode of operation aids in reducing the power consumption of the device,it can hinder reconnection of the relevant device to the network whenneeded.

Another power management scheme often employed by wireless devicesentails switching the NIC between different power states havingdifferent power consumption levels. Those states include high-powerstates, in which the NIC is powered up to enable the transmission ofnetwork communication data, and low-power states in which the networkinterface card is put in a sleep mode. Similar to the above-describedscenario in which the NIC is powered off, when the NIC is in a low-powerstate, data transmissions can be significantly delayed while the NICattempts to reconfigure with the network. Resultantly, the delayed datahas to be temporarily stored in a queue until the NIC is switched backto the high-power state where it is ready for data communication. Asignificant amount of delayed network traffic data may be accumulated inthe transmission queue if the interface network card is kept in thelow-power state too often, or for too long.

SUMMARY

To address the challenges described above, a method and system aredisclosed for reducing the battery consumption of computing devicescapable of communicating over a wireless network. Such wirelesscomputing devices include, but are not limited to, personal dataassistants, cellular phones, and laptop computers having wirelessnetwork interface capabilities.

In accordance with an embodiment of the invention, a wireless computingdevice enables a low power control channel to interpret signals forcontrolling the power usage of a network interface card (NIC), and otherpower consuming components of the computing device during idle periods.Idle periods are periods of low power operation for the computingdevice, or when no network activity (e.g., sending or receiving of data)is being engaged in by the wireless computing device via its highfrequency communication channel (e.g., 802.11 based channel). The lowpower control channel is implemented via an internal or external radiofrequency (RF) transceiver component, referred to as a minibrick, whichpreferably operates at a low frequency level. In operation, when thecomputing device is idle or in a low power state, the device isconfigured to power down all of its components with the exception of thecircuitry required to power the low power transceiver component. Assuch, the control channel is maintained in an active state for receivingsignals during both idle and non-idle periods. When another devicewishes to communicate with the wireless computing device, the low powercontrol channel receives a “wake-up” signal indicating that the NIC andother components of the computing device are to be powered up. Thiswake-up signal is received from another transceiver component, referredto as a smartbrick or host transceiver.

In accordance with another embodiment of the invention, the hosttransceiver operates upon a host computer to communicate with the lowpower transceiver operating upon the wireless computing device.Alternatively, the host transceiver operates at a device acting as awireless access point—an intermediate device that acts as an interfacebetween a server that manages and facilitates data communication overthe network, and the wireless device. In the former case, the hostcomputer is equipped with a low power NIC for supporting wirelesscommunication with the wireless device, and accesses the network via theaccess point (AP). When a requesting device wishes to communicate withthe wireless computing device, it first queries the server (e.g.,submits a subscription request) in order to determine the presence ofthe wireless computing device. In response, the server locates the pathto the wireless device via a host computer operating a low power NIC,and notifies the requesting device of its presence. Once the presence ofthe wireless computing device is known, the requesting device sends awakeup request to the server, and notifies the host computer. Next, thehost transceiver operating upon the host computer submits a low powerwakeup signal to the low power transceiver at the wireless device toprompt it to power up the device. In response, the wireless computingdevice powers up the high power, or standard NIC and other componentsaccordingly, resulting in activation of the wireless device prior to anyactual transmission of data by the requesting device.

Additional features and advantages of the invention will be madeapparent from the following detailed description of illustrativeembodiments that proceeds with reference to the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

While the appended claims set forth the features of the presentinvention with particularity, the invention and its advantages may bebest understood from the following detailed description taken inconjunction with the accompanying drawings, of which:

FIG. 1 is a schematic diagram of an exemplary computer network;

FIG. 2 is a schematic diagram illustrating the architecture of anexemplary computing device in which an embodiment of the invention maybe implemented;

FIG. 3 is a schematic diagram illustrating the basic architecture of atransceiver component operated by the computing device of FIG. 2 formaintaining a low power control channel in an embodiment of theinvention;

FIGS. 4 a and 4 b are schematic diagrams illustrating an exemplaryoperating environment for a wireless computing device to implement a lowpower control channel according to an embodiment of the invention;

FIG. 5 is a flowchart illustrating the operation of a host transceiverfor communicating with a wireless computing device via a low powercontrol channel according to an embodiment of the invention;

FIGS. 6 a and 6 b are diagrams illustrating an embodiment of theinvention for facilitating communication between two computing devices;and

FIG. 7 is a flowchart illustrating the operation of a low powertransceiver for communicating with another low power transceiver inorder to access a network according to an embodiment of the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

A method and system are described for reducing the battery consumptionof computing devices that are capable of communicating over a wirelessnetwork. Wireless computing devices usable within embodiments of theinvention include, but are not limited to, personal data assistants,cellular phones, and laptop computers having wireless network interfacecapabilities. In the context of the invention, wireless communication isthe transmission of data between computing devices using radio frequencyelectromagnetic waves rather than wires. To facilitate wirelesscommunication, a computing device may be equipped with a networkinterface card (NIC) that interfaces the device to the network.Typically, the NIC is implemented as a plug and play component that canbe inserted into a network interface (e.g., card slot) of the computingdevice. Alternatively, the NIC can be built integrally as part of thecircuitry of the wireless computing device.

To facilitate wireless communication, the NIC supports a wirelessprotocol, such as pursuant to the IEEE 802.11 standard. Generalreference will be made throughout the course of this description to802.11 as a suitable protocol for facilitating wireless communicationbetween devices. However, those skilled in the art will recognize that802.11 is only one protocol for facilitating wireless communication, andthat the invention is not limited to any one wireless protocol. Indeed,other wireless protocols may be utilized alternatively or additionallyin connection with the invention. It will also be recognized by thoseskilled in the art that 802.11 refers to other protocols within the samefamily, including 802.11a, 802.11b or 802.11g.

An example of a networked environment in which embodiments of theinvention may be used will now be described with reference to FIG. 1.The example network includes several computing devices 20 communicatingwith one another over a network 30, such as the Internet, as representedin the figure by a cloud. Network 30 may include one or more well-knowncomponents, such as routers, gateways, hubs, etc. and may allow thecomputers 20 to communicate via wired and/or wireless media.

Referring to FIG. 2, an example of a basic configuration for a computingdevice on which the system described herein may be implemented is shown.In its most basic configuration, the computing device 20 typicallyincludes at least one processing unit 42 and memory 44. Depending on theexact configuration and type of the computer 20, the memory 44 may bevolatile (such as RAM), non-volatile (such as ROM or flash memory) orsome combination of the two. This most basic configuration isillustrated in FIG. 2 by dashed line 46. Additionally, the computingdevice may also have other features/functionality. For example, computer20 may also include additional storage (removable and/or non-removable)including, but not limited to, magnetic or optical disks or tape.Computer storage media includes volatile and non-volatile, removable andnon-removable media implemented in any method or technology for storageof information such as computer-readable instructions, data structures,program modules, or other data. Computer storage media includes, but isnot limited to, RAM, ROM, EEPROM, flash memory or other memorytechnology, CD-ROM, digital versatile disk (DVD) or other opticalstorage, magnetic cassettes, magnetic tape, magnetic disk storage orother magnetic storage devices, or any other medium which can be used tostored the desired information and which can be accessed by thecomputing device 20. Any such computer storage media may be part of thecomputing device 20.

The computing device 20 preferably also contains communicationsconnections 48 that allow the device to communicate with other devices.A communication connection is an example of a communication medium.Communication media typically embodies readable instructions, datastructures, program modules or other data in a modulated data signalsuch as a carrier wave or other transport mechanism and includes anyinformation delivery media. By way of example, and not limitation,communication media includes wired media such as a wired network ordirect-wired connection, and wireless media such as acoustic, RF,infrared and other wireless media. The term computer readable media asused herein includes both storage media and communication media.

The computing device 20 may also have input devices such as a keyboard,mouse, pen, voice input device, touch input device, etc. Output devicessuch as a display 48, speakers, a printer, etc. may also be included.For wireless mobile devices used in an implementation of an embodimentof the invention, the computing device 20 is provided with a portablepower source 50, such as a battery pack, fuel cell or other powermodule. The power source 50 acts as a primary source of power forcomputations and wireless data transmissions to be performed by thedevice 20. When the device is described herein as “powered up,” thedevice battery is used to render the computing device 20 in an “ON”state of operation. Conversely, when the device is described as being“powered down,” the device is in an “OFF” state of operation, withlittle or no power being drawn by any component.

In accordance with an embodiment of the invention, the computing device20 is further equipped with a low power transceiver component 100 formaintaining a RF control channel, as illustrated in greater detail inFIG. 3. The low power transceiver component, referred to as a minibrick100, is comprised of various components for ensuring the receiving andsending of data, including a logic device 102 for controlling theoperation of the transceiver and for powering up the computing device 20in response to various network events. Also preferably included is avoltage regulator 104 for providing appropriate voltage from a low powerbattery unit 106. The low power battery unit 106 is suitable forpowering the low power transceiver using minimal power, and preferablyoperates independently of the portable battery source 50. Alternatively,the primary battery source 50 may be used to power the low powertransceiver. The low power transceiver 100 also includes a radiofrequency (RF) generator 108 for emitting and generating radio frequencysignals. Other elements 109 for implementing or enhancing thetransceiver functions may also be included as part of the low powertransceiver circuitry.

Physically, the low power transceiver 100 can be implemented as aninternal component of the computing device 20, such as by integrating itwith the primary motherboard of the computing device 20, or it can beconnected to the computing device via a peripheral connection (e.g., theinput channels 41). Also, the low power transceiver 100 is configured tosupport a control channel for receiving and sending data via the radiocomponent 108. Exemplary operating characteristics for the low powertransceiver 100 are shown in TABLE 1. TABLE 1 Example operationalcharacteristics for the low power transceiver 100. Data Rate 19.2 KbpsModulation 00 K Voltage 3 V Receiver Current 4.5 mA   Peak Radio OutputPower 0.75 mW As illustrated, the various characteristics of the low power transceiver100 result in the generation of a low power, and preferably lowfrequency, data communication channel such as at 915 MHz, supporting adata rate of 19 Kbps or other acceptable rate, which is less than thatof standard wireless NICs. Conventional NICs, such as those based on theIEEE 802.11 standard, operate at much higher data rates rangingapproximately from 1-54 Mbps. Because of the higher data ratesassociated with standard NICs, the battery usage required for poweringup the NIC is also higher. The low power transceiver 100, however,requires less power to operate, and is configured to remain active evenduring powered off states for the wireless computing device 20. Whilenot limited to the operating characteristics of TABLE 1, the low powertransceiver is suitable for generating and receiving RF signals withoutrequiring significant power usage by the device.

Referring now to FIG. 4 a, an exemplary network environment upon which awireless computing device, such as the device of FIGS. 2-3, may operateis shown in accordance with an embodiment of the invention. Theexemplary network includes a server 200, which interfaces with acomputer network 202 and manages various network resources including aBrick Server 201 and a location and presence server 203. Both the BrickServer 201 and location and presence server 203 reside at the server 200for facilitating specific network tasks. In particular, the location andpresence server (or presence server) maintains a list of clients thatare registered with the network server 200 in order to have theirpresence and network location information maintained. “Presence” refersto any data received over the network that describes the networkidentity, availability, physical location, activity level and/oroperating state of a computing device or corresponding user of a device.Essentially, any means by which the network server 200 can maintain acomputing device's presence, or map a computing device to a particularnetwork location is suitable for usage in the context of the invention.

Similar to the location and presence server 203, the Brick Server 201maintains and manages presence information pertaining to one or more lowpower transceivers or host transceivers. The low power transceiver andhost transceiver are low power RF components used to implement a lowfrequency band control channel within the network infrastructure. Theoperation of the host transceiver and low power transceiver will bedescribed in greater detail in later sections of the detaileddescription.

In addition to maintaining network resources, the server 200 alsofacilitates communication for one or more computing devices thatcommunicate over the network 202. A first client device 204 isconfigured to the network 202 through a wired connection (e.g., T1 line,modem), while the second client device, referred to herein as the hostcomputing device, accesses the network via an access point. Inparticular, the host computing device 206 connects to the network 202through a wireless connection 208 (e.g., 802.11 connection) or otherwiseto a wireless access point 210. The access point 210 acts as anintermediate device between the host computing device 206 and thenetwork infrastructure 202, to facilitate communication between the hostcomputing device 206 and the server 200. Also integrated with the hostcomputing device 206 is a host transceiver 212, which is a componentthat generates signals for communicating with low power transceiver 100.As described above, the host transceiver 212 is connected to the network202 via the client device 206.

In an alternate embodiment of the invention, the host transceiver 212can be integrated with the wireless access point 210 directly forcommunicating with the low power transceiver 100. In either case, oncethe host transceiver is integrated with the access point 210 or with thehost computing device 206 (either internally or externally), the hosttransceiver 212 is registered with the Brick Server 203 maintained bythe server 200 in order to report its presence. The host transceiver,being connected to the network via a host computing device 206, as shownin the illustrated embodiment, may be able to detect various networkevents. This includes network events such as the transmission of amessage to the host computing device 206 or access point, an update toany presence information maintained by the Brick Server 203, thetransmission of messages intended for transmission by the access point210, and any other statistics relative to the performance of the network202.

In accordance with an embodiment of the invention, a wireless computingdevice operating a low power transceiver 100 communicates with the hosttransceiver 212 via a low power control channel, as shown in FIG. 4 b.The wireless computing device is a handheld device 220 having wirelesscomputing capabilities. The low power transceiver 100 provides a lowpower, preferably low frequency band control channel. The low powertransceiver 100 is enabled to remain powered up especially duringinactive or idle periods for the wireless computing device 220 in whichthe device is predominantly powered off. Also, the low power transceiver100 is capable of activating the wireless computing device 220 inresponse to “wake up” signals and other control signals.

To enable the low power transceiver 100 to engage in communicationwithin the network 202 over a low power control channel, the low powertransceiver 100 should first register with the Brick Server 203maintained by the server 200. A user of the wireless computing device220 can enable the registration process manually, such as by running anetwork application on the device 220 that engages the registrationprocess. Alternatively, the registration process can be performedwithout user intervention through a simple communication scheme engagedin by the host transceiver 212 and low power transceiver 100, asdescribed below.

To determine whether a low power transceiver requires registration, thehost transceiver 212 periodically broadcasts beacon or detection signalsindicating that the host transceiver is within a suitable range forengaging in communication via the low power control channel. Thisperiodic detection signal is sent during times at which the hosttransceiver 212 is not transmitting other types of control signals ordata. When the low power transceiver 100 operating at the wirelesscomputing device 220 detects the host transceiver 212 detection signal,the low power transceiver 100 generates and sends a message to the hosttransceiver 212 indicating that it is in the vicinity of the hosttransceiver 212. Upon receiving this message, the host transceiver 212makes a determination as to its capability to “manage” the low powertransceiver 100, and then replies to the low power transceiver 100 withan acknowledgement message if appropriate. A response acknowledgement isthen generated and sent to the host transceiver 212 by the low powertransceiver 100, which results in an association (connection or link)between the two transceivers. Having established an association betweenthe host transceiver 212 and low power transceiver 100, the hosttransceiver transmits a message to the presence server 201 to inform theserver of the presence of the low power transceiver 100.

Regardless of the method of registration performed, be it as describedabove or by way of another technique, the wireless computing device 220operating the low power transceiver 100 must be within a range suitablefor receiving signals from and transmitting signals to the hosttransceiver 212. This range will vary based upon the specific designcharacteristics of the low power transceiver 100 and host transceiver212. Note that the messages passed between the low power transceiver 100and host transceiver 212 (e.g., acknowledgement messages) aretransmitted over a low power, low bandwidth, communication channel, andnot the primary communication channel of computing devices 206 and 220that the host transceiver 212 and low power transceiver 100 reside uponrespectively. Consequently, the high power NIC card of the wirelesscomputing device 220 need not be used for facilitating the presencedetection and registration process, resulting in less power usage by thedevice. Also, because the registration process is executed via a lowpower control channel rather than the high power wireless connection,the wireless computing device operating the low power transceiver 100need not be powered up during the time.

Also, for reducing the power consumption of the wireless computingdevice 220, the low power control channel may be shut down duringnon-idle periods of operation by the wireless computing device 220. So,for example, when a NIC card is active at the computing device 220 forfacilitating normal (high power) wireless communication such as pursuantto the 802.11 standard between the wireless computing device 220 and thenetwork 202, the low power transceiver 100 can be powered down or placedinto a nominal power mode (e.g., sleep mode of operation). Once thewireless computing device 220 becomes idle, the low power transceiver100 can be powered up to resume its normal operation. In this way, thereis no concurrent power usage by the wireless computing device inmaintaining both the NIC and the low power transceiver in a powered upstate in an embodiment.

The presence detection and registration process described above relatesto the presence of the low power transceiver 100 and not expressly tothe presence of the wireless computing device 220. However, thoseskilled in the art will recognize that detecting and registering thepresence of a low power transceiver 100 provides an indication of thepresence of the associated wireless computing device as well. Anembodiment of the invention for controlling the power usage of thewireless computing device 220 operating a low power transceiver 100 willbe described hereinafter with reference to FIG. 4 b and the flowchart ofFIG. 5.

Reducing Power Consumption of Low Power Transceiver Enabled Devices

In FIG. 4 b, a control channel is shown to exist between the low powertransceiver 100 of the wireless computing device 220 and the hosttransceiver 212, as represented by the bolted arrow 222. In this state,the host transceiver 212 is aware of the low power transceiver's 100presence, and that the two are capable of exchanging data and controlsignals with one another. The control channel 222 remains active whetherthe wireless computing device 220 is predominantly powered off or on, oralternatively, can be powered down when the device is non-idle, i.e.predominantly powered on, as discussed above. In general, the computingdevice 200 is off when it is engaged in no activity over the network orwhen it is not in operation by the user. This operational state of thewireless computing device, wherein the device is significantly powereddown or completely shut off due to lack of network or user activity isknown to as an idle state.

A first client device 204 wishing to communicate with the wirelesscomputing device 220 over the network 202 when the wireless computingdevice 220 is idle can do so by sending a wake up request to the hosttransceiver 212. Occasions on which a wake up request is sent to thehost transceiver 212 by the first client device 204 may vary. Forexample, such a request can be sent to the host transceiver 212 in orderto wake up the wireless computing device 220 prior to the transmissionof a message by the first client device 204 to the wireless computingdevice 220 via a standard NIC connection between the access point 210 orhost 206 and device 220. Waking up the wireless computing device 220before the message is sent can avoid data transmission delay. When thefirst client device 204 wants to determine the presence of low powertransceiver 100 in order to transmit a wakeup message, it queries theserver 200 for this information. In response to this request, the server200 sends the presence information maintained by the Brick Server 203 tothe first client device 204. The presence information can include, butis not limited to, data such as the identity of the low powertransceiver 100 and/or its associated device, its location, and theidentity and location of the host computer 206 and host transceiver 212that the low power transceiver 100 communicates with. After receivingthis information, the first client device 204 sends a request to thehost transceiver 212 via the host computer 206 requesting that thewireless computing device 220 be awakened. This occurrence correspondsto event 250 of the flowchart of FIG. 5.

When the host transceiver 212 receives the wake up request, it generatesa corresponding wake up message to alert the low power transceiver 100that it must power up the wireless computing device 220 (event 252).This message is then transmitted to the low power transceiver 100 overthe low power control channel 222 in step 254. Upon receiving the wakeup message, the low power transceiver 100 powers up the wirelesscomputing device accordingly (event 256). This includes powering up thestandard NIC of the device 220 to enable communication over the highdata-rate, high-power network 202.

The communication between the host transceiver 212 and the low powertransceiver 100 via the low power control channel 222 for controllingthe power usage of the wireless computing device 220 has been discussedabove. However, the ability of the host transceiver 212 and low powertransceiver 100 to communicate by way of a low power control channel 222requires that they be within radio range of one another. While theinvention is not limited to any particular range, it is preferable thatthe low power transceiver of the wireless computing device 220 be closeenough to a host transceiver enabled host computer 206 to ensure RFsignal reception and data integrity. However, it is still possible tohave such low power communications even when the relevant low powertransceiver is not within direct communication range with the RFtransceiver 212 operating at a host computer. Techniques forfacilitating out-of-range communication are discussed in the followingsection of the detailed description.

Controlling Out-of-Range Low Power Transceivers

In FIG. 6 a, a first wireless computing device 300 operating a low powertransceiver 302 is shown to be out of a suitable direct range forsupporting communication with a host computer 306 operating a hosttransceiver 308. As such, the low power transceiver 302 is unable toregister with the server 304 to enable its presence information to beconveyed with other devices over the network 310, as described earlier.In accordance with an embodiment of the invention, however, the firstwireless computing device 300 is able to communicate with the server 304using multi-hop networking, as illustrated in FIG. 6 b and thecorresponding flowchart of FIG. 7. Specifically, when a second wirelesscomputing device 312 operating a low power transceiver device 314 iswithin range of the host computer 306 operating the host transceiver308, the device 312 is registered with the Brick Server 305 (event 400of FIG. 7). Subsequently, a low power control channel 316 is establishedbetween the second computing device 312 and host transceiver enableddevice 306.

When the second wireless computing device 306 is also within range ofthe first wireless computing device 300, the low power transceiveroperating on the first wireless computing device 300 establishes contactwith the second wireless computing device 312 via a low powercommunication channel. In particular, the low power transceiver 302 ofthe first wireless computing device 300 sends a message to the low powertransceiver 314 of the second wireless computing device 312 requestingthat it be allowed to access the Brick Server 305 (event 402). The lowpower transceiver of the second wireless computing device 312 then makesa determination as to whether to acknowledge and accept this request(event 404). If the request is accepted, a control channel 318 isestablished between the first and second wireless computing devices 300,and 312 (event 406). The low power transceiver 302 associated with thefirst wireless computing device 300 sends a registration message to thesecond wireless computing device 312 (event 408). This message is thenforwarded by the second wireless computing device 312 to the hosttransceiver 308 operating upon the host computer 306, and to the BrickServer 305 (event 410). Once the registration of the low powertransceiver 302 for the first wireless computing device 300 is recordedby the server 304, the first wireless computing device 300 is able toengage in communication with other devices over the network 310.

Those skilled in the art will recognize that the above describedprocesses can be carried out within an environment of several wirelesscomputing devices and not just between two. As will be appreciated bythose skilled in the art, whenever a number of wireless computingdevices are within an appropriate low power radio range of one another,multi-hop communication can ideally be engaged by an unlimited number ofsuch devices. This is particularly advantageous in the case of mobilewireless computing devices, such as PocketPCs, wherein a directconnection to a host transceiver enabled host 306 may be limited as thedevice user roams from one location to another. By connecting to theserver via another low power transceiver enabled device, the low powercontrol channel can still be activated for facilitating reduction ofpower consumption of a device.

In view of the many possible embodiments to which the principles of thisinvention may be applied, it should be recognized that the embodimentsdescribed herein with respect to the drawing figures are meant to beillustrative only and should not be taken as limiting the scope ofinvention. For example, those of skill in the art will recognize thatthe elements of the illustrated embodiment shown in software may beimplemented in hardware and vice versa or that the illustratedembodiment can be modified in arrangement and detail without departingfrom the spirit of the invention. Therefore, the invention as describedherein contemplates all such embodiments as may come within the scope ofthe following claims and equivalents thereof.

1.-4. (canceled)
 5. A method for communicating with a wireless computingdevice over a network comprising a secondary communication channel, thesecondary communication channel being a radio frequency channel operableby the wireless computing device and requiring less power usage by thewireless computing device than a primary communication channel alsooperable by the wireless computing device, the method comprising:detecting the presence of a low power transceiver operating upon thewireless computing device; and transmitting a message to the wirelesscomputing device via the secondary communication channel based on thepresence of the low power transceiver, whereby in response to thetransmitted message a message is transmitted from the wireless computingdevice via the primary communication channel.
 6. The method of claim 5wherein detecting the presence of a low power transceiver operating uponthe wireless computing device further comprises determining whether thewireless computing device is within radio range over the secondarycommunication channel of a host transceiver via the low powertransceiver.
 7. The method of claim 6 wherein the host transceiver isoperable by a host computer and is communicably linked with the remotecomputing device via a network.
 8. The method of claim 6 whereindetermining whether the wireless computing device is within radio rangeover the secondary communication channel of a host transceiver via thelow power transceiver further comprises broadcasting a detection signalvia the secondary communication channel.
 9. The method of claim 8wherein the detection signal is transmitted when the host transceiver isnot transmitting other types of signals via the secondary communicationchannel.
 10. The method of claim 5 wherein detecting the presence of alow power transceiver operating upon the wireless computing devicefurther comprises transmitting a message to a presence server, themessage indicating the presence of the low power transceiver.
 11. Themethod of claim 5 wherein detecting the presence of a low powertransceiver operating upon the wireless computing device furthercomprises querying the presence server for presence informationpertaining to the low power transceiver.
 12. The method of claim 5wherein the message transmitted by the remote computing device indicatesthat the wireless computing device is to be activated from a low powerstate of operation.
 13. A system for communicating with a wirelesscomputing device via a secondary communication channel, the secondarycommunication channel being a radio frequency channel operable by thewireless computing device and requiring less power usage by the wirelesscomputing device than a primary communication channel also operable bythe wireless computing device, the system comprising: means fordetecting the presence of the wireless computing device via thesecondary communication channel; and means for transmitting a message tothe wireless computing device via the secondary communication channelbased on the presence of the low power transceiver, whereby in responseto the message a reply message is transmitted to the wireless computingdevice via the primary communication channel.
 14. The system of claim 13wherein said means for transmitting a message comprises communicationfacilities of a computing device remote from the wireless computingdevice, and wherein said means for detecting is operable by a hostcomputer that is communicably linked with the remote computing devicevia a network.
 15. The system of claim 14 wherein the host computercomprises means for broadcasting a detection signal via the secondarycommunication channel, the detection signal indicating whether thewireless computing device is within a physical range suitable forenabling said means for detecting to communicate with the wirelesscomputing device via the secondary communication channel.
 16. The systemof claim 13 wherein said means for detecting further comprises means formaintaining presence information associated with one or more radiotransceivers operable by one or more wireless computing devices capableof communicating via the secondary communication channel.
 17. The systemof claim 13 wherein said means for transmitting is communicably linkedwith a host computer via the primary communication channel.
 18. Thesystem of claim 17 wherein the host computer comprises means forgenerating a corresponding message in response to a message receivedfrom said means for transmitting, the corresponding message indicating arequest for the wireless computing device to perform an action, thecorresponding message being transmitted to the wireless computing devicevia the secondary communication channel. 19.-34. (canceled)